Tell you what, here are some photos for you to think about.
This was my first car, a 1986 Chevy S-10 Blazer. No airbags, I think ABS was still practically brand new that year:
Then, while driving down a road going
only 45mph, a lady pulls out from a side street right in front of me, and I t-bone her SUV.
Here's the aftermath:
The dent above is where the back of her SUV spun around and hit the side of my vehicle in a secondary impact.
I was wearing my seatbelt and walked away from the collision. I had a sore right foot (from jamming on the brake pedal right before impact) and later a sore neck from the whiplash. I also had major seatbelt burn on my right hip.
I was travelling in the left lane (to the right of the center turn lane) of a 6-lane undivided major thoroughfare. There was traffic travelling the opposite direction of me in the three lanes, presumably also going 45mph.
Because I had my seatbelt on, I was able to continue holding the brake pedal to the floor, and stopped my vehicle before it rolled into the oncoming traffic.
Let me be very clear, this collision was very violent. In fact, I can still remember watching my sunglasses fly off of my face and landing in the front passenger's footwell like it was in slow motion.
If I hadn't been wearing my seatbelt, I would be dead or very severely injured. I have no doubt about that. If I hadn't been wearing my seatbelt, I would not have been able to continue holding the brake pedal down, and my vehicle would have rolled directly into oncoming traffic. And if I had rolled into oncoming traffic, that collision would most certainly have injured more than just myself, in a collision that wasn't even my fault to begin with.
I am done with this argument. If you want to drive without your seatbelt, then fine, do what you want. But I will have absolutely no sympathy for you when you get a traffic ticket for it or, God forbid, when the day comes that you have that sudden realization that you were dead wrong about how not wearing your seatbelt can't hurt anyone other than yourself.
Edit: I've attached an image of the intersection where my collision happened. My collision was in June of 2003, and the city has since made the center lane a concrete median because apparently what happened to me was a common enough occurrence to warrant dividing the traffic with a median.